text: """Custom user functions."""
  import pandas as pd
  
  # all your functions will ggo here.........
  
  filename = 'data/transaction_report.csv'
  
  
  def read_data_file():
      """Read data file."""
      main_data = pd.read_csv(filename, encoding='utf-8')
      return main_data
  
  
  def get_filter(main_data, filtername='Month'):
      """Get filter params."""
      filters = main_data[filtername].unique()
      return filters
  
  
  def filter_data(data):
      """Responsible for filtering all filter data."""
      return data
  
  
  def get_filter_str(handler):
      """Create the complete filter str including previous filters."""
      return ''
  
  
  def barchart_data(handler):
      """Create a bar chart."""
      # print get_argument("month", None, True)
      main_data = read_data_file()
      full_data = main_data
      main_data = filter_data(full_data)
      return full_data, main_data
  